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Title: Wave-wave interactions in solar type III radio bursts

The high time resolution observations from the STEREO/WAVES experiment show that in type III radio bursts, the Langmuir waves often occur as localized magnetic field aligned coherent wave packets with durations of a few ms and with peak intensities well exceeding the strong turbulence thresholds. Some of these wave packets show spectral signatures of beam-resonant Langmuir waves, down- and up-shifted sidebands, and ion sound waves, with frequencies, wave numbers, and tricoherences satisfying the resonance conditions of the oscillating two stream instability (four wave interaction). The spectra of a few of these wave packets also contain peaks at f{sub pe}, 2f{sub pe} and 3 f{sub pe} (f{sub pe} is the electron plasma frequency), with frequencies, wave numbers and bicoherences (computed using the wavelet based bispectral analysis techniques) satisfying the resonance conditions of three wave interactions: (1) excitation of second harmonic electromagnetic waves as a result of coalescence of two oppositely propagating Langmuir waves, and (2) excitation of third harmonic electromagnetic waves as a result of coalescence of Langmuir waves with second harmonic electromagnetic waves. The implication of these findings is that the strong turbulence processes play major roles in beam stabilization as well as conversion of Langmuir waves into escaping radiationmore » in type III radio bursts.« less
Authors:
 [1] ;  [2]
  1. Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)
  2. NASA/Goddard Space Flight Center, Greenbelt MD 20771 (United States)
Publication Date:
OSTI Identifier:
22263919
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1582; Journal Issue: 1; Conference: International conference on complex processes in plasmas and nonlinear dynamical systems, Gandhinagar (India), 6-9 Nov 2012; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COALESCENCE; ELECTROMAGNETIC RADIATION; INTERACTIONS; LANGMUIR FREQUENCY; MAGNETIC FIELDS; PEAKS; RESONANCE; SOUND WAVES; SPECTRA; TIME RESOLUTION; TURBULENCE; TWO-STREAM INSTABILITY; WAVE PACKETS